we use redhat here at work (i work for an ISP/Information provider), but will never give slackware up for it.
in fact, here's a nice little problem we ran into this morning:
my boss calls me at 6am, saying our database server is down and none of the onsite techs can fix it. so i had to haul arse to work, and discover that the server runs kernel panic errors on boot. at first we thought it was a problem with the scsi controllers, but then i noticed the kernel it was trying to boot to wasn't the same as the one it was using 2 weeks ago.
long story short, we subscribe to the redhat network, and overnight up2date ran, downloaded, and installed a new kernel. the "new" kernel wasn't at all configued for the system, nor was grub (YUK) even pointing to the right root partition.
needless to say, i'm in the process of trying to convince management to migrate to slackware, so we can avoid these fscking idiotic server problems (this is the 3rd crash we've had related to RHN this week alone).
if you can't get it done right, do it yourself. and redhat sure as hell can't get it done right... or at least RHN.